Electrical junction box for a vehicle

ABSTRACT

An electrical junction box for a vehicle has a casing, and an electrical circuit. The electrical circuit has a fuse connection circuit, a relay connection circuit and a connector connection circuit. The casing has, at opposite sides, connector sockets for electrical connectors. A connector module in the casing has a plurality of insulation substrates stacked one on another and parallel elongated bus bars on a first surface of each substrate and parallel flexible conductors on a second surface of the substrate, which extend orthogonally to the bus bars. Each insulation substrate has apertures through it at which the bus bars and flexible conductors are connected to each other to provide desired circuit connections. The bus bars extend from the insulation substrates and provide tabs projecting into the connector sockets. A thin junction box is obtained.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to an electrical junction box for avehicle, in particular a box to be connected to a wire harness for avehicle. The invention is intended to provide a junction box which isthin and compact even though the number of circuits is increased. Theinvention also provides a vehicle, such as an automobile, having theelectrical junction box mounted on it.

2. Description of Related Art

Recently, the rapid increase in the number of electric and electroniccomponent parts which are mounted on a vehicle has led to increase inthe number of circuits to be accommodated in a junction box in thevehicle. When forming branch circuits at high density, it is necessaryto mount a large number of component parts on the junction box, whichincreases the number of assembly stages.

The assignees of the present application proposed the junction box 1shown in present FIG. 21 in JP-A-2000-112691 (corresponding toEP-A-1145914 and U.S. patent application Ser. No. 09/833595). Thejunction box of FIG. 21 is intended to be thin, capable of permittingcircuit alteration and reducing the time and labor required for itsassembly from component parts.

In the junction box 1 of FIG. 21, a connector connection circuit (basecircuit), a fuse connection circuit, and a relay connection circuitprovided in the junction box are formed separately as a connector module2, a fuse module 3 and a relay module 4. The connector module 2, thefuse module 3 and the relay module 4 are incorporated in the casingcomposed of the lower case part 5 and the upper case part 6.

In each of the connector module 2, the fuse module 3 and the relaymodule 4, bus bars 2 b, 3 b and 4 b are fixed to insulation substrates 2a, 3 a and 4 a respectively, and project from the periphery of theinsulation substrates to which they are attached.

Because the whole circuit of the junction box is divided into theconnector module 2, the fuse module 3 and the relay module 4, overlap ofthe bus bar tabs can be avoided. Thus, the formation of multiple layersof bus bars can be prevented. Therefore, the junction box can be thin,and the circuits of the bus bars can be more easily wired. Thus, it ispossible to reduce the area of the bus bar for module. Consequently,even though the connector connection bus bars, the fuse connection busbars and the relay connection bus bars are formed separately, the totalarea of all the bus bars can be reduced and the area of the junction boxcan be kept to a minimum.

Further, when the specification of any one of the connector circuit, thefuse circuit and the relay circuit is altered, it is only necessary toalter the respective module. Thus, the junction box permits alterationof the specification easily.

However, the bus bars used as electrical conductors in the modules aregenerally formed by punching metal sheet into a form corresponding to acomplicated configuration of the circuit of the module. Thus, the yieldof the metal sheet is low. Further, when a circuit alteration is made,it is necessary to make a new punching die, which can increase costs.

Further, depending on a circuit configuration, it may be impossible toform the circuit as a single layer. Thus the number of bus bar layersincrease.

For example, as shown diagrammatically in FIG. 22A, in connectingcircuits C1 and C2 to connectors 7A and 7B of a connector module 2 andto a fuse 8 of a fuse module 3 disposed on the side of the connectormodule, the circuits C1 and C2 of the connector module 2 cannot beconnected to the fuse 8 unless the circuits C1 and C2 are disposed inseparate layers. Thereby, the number of layers is increased.

Although the number of component parts mounted on a vehicle hasincreased rapidly, space for the junction box has remained limited.Thus, it is essential to make the junction box as thin as possible.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a junction box whichis thin and can be manufactured at a low cost, in particular byimproving the yield of a conductive metal plate.

It is a further object of the invention to simplify the wiring andconductor arrangements in a junction box and provide simplified methodsof making the connector module of the junction box.

According to a first aspect of the invention in, there is provided anelectrical junction box having a casing and an electrical circuit in thecasing adapted to make electrical connection, in use, to electricalconnectors, fuses and relays. The electrical circuit comprises a fuseconnection circuit, a relay connection circuit and a connectorconnection circuit, which is electrically connected to the fuseconnection circuit and the relay connection circuit. The casingcomprises a fuse circuit portion, containing the fuse connectioncircuit, and a relay circuit portion, containing the relay connectioncircuit. The casing also has two laterally opposite sides, each of whichforms a connector accommodation portion adapted to receive, in use, atleast one electrical connector.

Additionally, the electrical junction box may further have, mountedwithin the casing, a connector module providing the connector connectioncircuit that comprises a plurality of insulation substrates stacked oneon another and each having a first main surface and a second mainsurface opposite the first main surface. A plurality of parallelelongate bus bars may be arranged on the first main surface of eachsubstrate and extends in a first direction, and a plurality of parallelflexible conductors may be arranged on the second main surface of eachinsulation substrate and extends in a second direction orthogonal to thefirst direction. A plurality of apertures pass through each insulationsubstrate from the first main surface to the second main surface. Thebus bars and the flexible conductors are connected to each other bywelding to provide desired circuit connections at these apertures. Thebus bars of each insulation substrate are oriented in the lateraldirection of the casing between the opposite sides, some which extendfrom the insulation substrates in the first direction and provide tabsthat project into the connector accommodation portions.

The flexible conductors of each connector module may be single-corewires, or conductors of a flexible flat cable arranged on the secondmain surface of the insulation substrate, the flexible flat cablecomprising flexible insulation material in which the conductors areheld.

Thus in the connector module, the elongated bus bars and the flexibleconductors cross each other, with the insulation substrate interposedbetween them, and are connected to each other at crossing positions toform the circuit of the connector module. Thus, it is possible to setthe interval between the bus bars equal to the interval between theterminals of a connector to be attached to the box, in use. Thus, thetabs formed at both ends of the bus bars can project horizontally intothe connector accommodation portion formed on the side surface of thebox, with or even without bending the tabs.

In the circuit shown in FIG. 22B, in comparison with that of FIG. 22A,the conductors 21 can be connected to the fuses 35 while connecting bothends of the bus bars 22, constituting circuits C1 and C2, of theconnector module 11 to connectors 7A′ and 7B′. Thus, it is possible toconnect the bus bars 22 to the conductors 21, disposed on the other sideof the insulation substrate 20, orthogonally to the bus bars 22, withthe insulation substrate 20 interposed between the bus bars 22 and theconductors 21. Consequently, this simple circuit of the connector module11 can be formed from a single circuit layer having the bus bar disposedon one surface of the insulation substrate and the conductors disposedon the other surface thereof. This simple example illustrates theprinciple of this aspect of the invention. That is, it is possible toreduce the number of layers of the bus bar to produce a thin junctionbox.

Even though the connector accommodation portion is formed on the sidesurface of the box, the tabs of the bus bars can project into theconnector accommodation portion at the side surface of the side casewithout interference from adjacent tabs or deformation thereof. Further,even though the connector is disposed on the side surface of the box,the bus bars can be disposed in a simple construction. Thus, a relayterminal for connecting bus bars interlaminarly is unnecessary and theconstruction of the circuit of the connector module can be kept simple.

The number of layers of the substrates of the connector module may beequal to the number of rows of terminals of a connector which fits inthe connector accommodation portion.

That is, as described above, the tabs formed at both ends of the bus bardisposed on one surface of each substrate of the connector moduleproject into the connector accommodation portions. Thus, the number oflayers of the substrates of the connector module may be equal to thenumber of rows (stages) of terminals of the connector, which fits in theconnector accommodation portion. In other words, the connector can beeasily disposed on the side surface of the box when the number of therows (stages) of the connector is equal to the number of the substrates.

A further layer consisting of bus bars may be formed as an additional,e.g. lowermost layer, of the connector module. The total of the numberof layers of the substrates and the number of further layers of the busbars may be not less than the number of rows (stages) of terminals ofthe connector which fits in the connector accommodation portion.Preferably, the elongate bus bars are not connected to the power sourceside and to the power supply side of the fuses. For efficient wiring ofthe bus bars, it is preferable to use one bus bar having a plurality offuse connection terminals formed at one end thereof. Thus as the bus barhaving a plurality of fuse connection terminals formed at one endthereof, it is preferable not to use the elongate bus bars but use thebus bars formed by punching a conductive metal plate corresponding tothe configuration of a desired circuit. The elongate bus bars may bedisposed on a layer on which the bus bar formed by punching theconductive metal plate is disposed, and the ends of the elongate busbars project horizontally as tabs. Consequently, the total of the numberof the substrates and the number of the further layers of the bus barsis equal to the number of the rows (stages) of terminals of theconnector.

The ends (tabs) of the elongate bus bars that project into the connectoraccommodation portion may be kept flat, so that the tabs of differentbus bar layers do not interfere with each other. Otherwise, if the tabsare bent and project from the bus bars disposed on one substrate, thetabs may interfere with tabs projected from the substrates of otherlayers.

However, bent tabs a bus bar that project into the connectoraccommodation portion may be may be accommodated if bent in a mannerthat kept the tab horizontal, e.g. in the shape of a letter “L” or asingle zig-zag. By bending the tabs of the same layer in the sameconfiguration and arranging the tabs to remain parallel with oneanother, and bending the tabs of the bus bars from other layers in thesame configuration, interlaminar interference between the tabs isavoided.

Compared to the conventional process of forming bus bars, such as bypunching a conductive metal plate corresponding to the configuration ofa circuit, it is possible to improve the yield of the conductive metalplate considerably, by employing strip-shaped elongate bus bars ofuniform width. Further, the construction can cope with alteration of thecircuit construction by simply changing the position where the flexibleconductors and bus bars cross each other and are welded to each other.Because it is unnecessary to alter the conductive material itself withthe change of the circuit construction, the construction can easilypermit alteration of the circuit construction without increasing themanufacturing cost.

According to a second aspect of the invention in there is provided anelectrical junction box having a casing, and an electrical circuit inthe casing adapted to make electrical connection, in use, to electricalconnectors, fuses and relays. The electrical circuit comprises a fuseconnection circuit, a relay connection circuit and a connectorconnection circuit which is electrically connected to the fuseconnection circuit and the relay connection circuit.

The casing comprises a fuse circuit portion, containing the fuseconnection circuit, and a relay circuit portion, containing the relayconnection circuit. The electrical junction box may further comprise aconnector module, mounted in the casing, which provides a connectorconnection circuit that comprises at least one insulation substratehaving a first main surface and an opposite second main surface, and aplurality of spaced parallel flexible conductors arranged on the secondmain surface. The relay connection circuit comprises a plurality of busbars, each having one end arranged to make a connection, at least, inuse, to relays and another end that constitutes a pressure connectionterminal, which is connected by pressure connection directly tointermediate points of at least some of the flexible conductors of theconnector module. In this construction, the connector module is formedwith spaced conductors, e.g. parallel with one another, and the pressureconnection terminals at the ends of the bus bars of the relay connectioncircuit are connected to the intermediate points of the conductors bypressure connection, which reduces the number of welded connectionsrequired.

The ends of the conductors of the connector module may be connected,e.g. by pressure connection, to the terminals formed at an end of thebus bars of the fuse module, and through relay terminals the other endsof the conductors may be connected to an electronic control unitaccommodated in the junction box. Thereby the circuit of the connectormodule can be connected to the relay module, the fuse module and theelectronic control unit by pressure connections between the conductorsand the terminals. By effectively utilizing the one end, theintermediate portion and the other end of the conductors of theconnector module, the circuit of the connector module can be connectedto the relay module, the fuse module and the electronic control unit bypressure connections instead of welding bus bars to each other. Thus, itis easy to perform a circuit connection operation. Further, it ispossible to solve the problem of warping of the bus bars, which occursdue to the thermal strain to which the bus bars are subjected when theyare welded together.

The pressure connection terminals at the ends of each of the bus bars,connected to terminals of the relays of the relay module respectively,are preferably arranged in parallel with one another and connectedrespectively by pressure connection to the conductors, which areparallel in the connector module. This construction allows theconnection between the circuit of the relay module and that of theconnector module to be accomplished in a one-time pressure connectionoperation.

The relay module may be of a direct mounting type. That is, the relaymay be mounted on a body having a bus bar formed by insert moulding. Aterminal of the relay penetrates through apertures formed in the bodyand the bus bar, and the terminals of the relay may then be soldered tothe bus bar. This construction allows the height of the relay to be keptto a minimum. Thereby it is possible to make the junction box thin.

The preferred layout of the junction box would have the connector modulemounted in the lower portion of the casing, the fuse circuit portionlocated laterally of the connector module at a first side of the casing,the relay circuit portion located above the connector module at thefirst side of the casing, an electronic control unit mounted in thecasing above the connector module, the connector accommodation portionof the casing, to receive at least one electrical connector, in use,located at a further side thereof, extending orthogonally to the firstside thereof, and the bus bars of the connector module project into theconnector accommodation portion to constitute tabs therein forconnection to the connector, in use.

According to a third aspect of the invention in there is provided anelectrical junction box having an electrical circuit adapted to makeelectrical connection, in use, to electrical connectors, fuses andrelays. The electrical circuit comprises a fuse connection circuit, arelay connection circuit and a connector connection circuit, which iselectrically connected to the fuse connection circuit and the relayconnection circuit. At least one of either the fuse connection circuit,the relay connection circuit and the connector connection circuitcomprises a circuit module having a plurality of elongate bus barsarranged parallel to each other and extending in a first direction. Aplurality of flexible conductors arranged parallel to each other andcrossing the bus bars are arranged in a second direction, orthogonal tothe first direction, where the flexible conductors and the bus bars areelectrically connected to each other at a plurality of their mutualcrossing points to provide the desired circuit connections.

The layout allows the side surface of the junction box to be effectivelyutilised. Thereby it is possible to make the junction box thin.

Conventionally, a conductive metal plate is punched in a shapecorresponding to the configuration of a circuit to form an electricconductor. But according to this aspect of the present invention, thedesired circuit can be formed by crossing the elongate bus bars and theflexible conductors and connecting them to each other at necessarycrossing points. Therefore, there is little loss of the conductive metalplate and it is possible to greatly improve the yield of the conductivemetal plate. In addition, when it is necessary to change theconstruction of the circuit, it is not necessary to alter the conductorsbut it is only necessary to change the position where the bus bars andthe flexible conductors are connected to each other. Accordingly, thejunction box of the present invention can be manufactured at a low costand can cope with the alteration of the circuit. At the crossing points,the bus bars and the conductors, e.g. single-core wires, may be joinedto each other in openings formed in the insulation substrate byresistance welding or soldering.

In the case where a bare wire is used as the flexible conductor, it isunnecessary to remove an insulating coating at the position where thewire and the bus bar are connected to each other. However, it ispossible to use wire having a core wire coated with an insulationcoating material. Alternatively, the flexible flat cable describedherein above may be used.

Optimally, the wires and the bus bars may be connected to each other byresistance welding in the openings formed in the insulation substrate.However, soldering may be used as described above. In addition,ultrasonic welding, gas welding or laser welding may also be used.

The circuit module may have a plurality of circuit substrates layeredone upon another with insulation interposed between the circuit platesadjacent to each other, with each of the circuit substrates havingflexible conductors disposed on one surface and elongate bus barsdisposed on the other surface.

The invention further provides a method of forming an electrical circuitmodule comprising the steps of: fixing a plurality of bus bars to afirst main surface of each of a plurality of insulation substrates;arranging flexible conductors on a second main surface opposite thefirst main surface of each insulation substrate, while the insulationsubstrates are arrayed in a row, with the flexible conductors extendingcontinuously over the insulation substrates in said row; connecting thebus bars to the flexible conductors at mutual crossing points thereofvia apertures in the insulation substrates to form desired circuitconnections; bending the portions of the flexible conductors thatextending between adjacent pairs of the insulation substrates to bringthe insulation substrates into a stack one above another; and removingportions of said flexible conductors not wanted in the completedcircuit.

By forming the circuit module in the manner described, the flexibleconductors may be wired collectively or continuously and operability ofthe method can be greatly improved.

According to another aspect of the invention, there is provided anelectrical junction box having an electrical circuit adapted to makeelectrical connection, in use, to electrical connectors, fuses andrelays. The electrical circuit comprises a fuse connection circuit, arelay connection circuit and a connector connection circuit, which iselectrically connected to the fuse connection circuit and the relayconnection circuit. The electrical junction box may comprise a connectormodule providing the connector connection circuit, which comprises aninsulation substrate having a first main surface and a second mainsurface opposite the first main surface, and a plurality of firstelectrical conductors on the first main surface and a plurality ofsecond electrical conductors on the second main surface. The firstelectrical conductors are parallel to each other and can extend in afirst direction and the second electrical conductors are parallel toeach other and extend in a second direction, orthogonal to the firstdirection. Thus, the second electrical conductors cross the firstelectrical conductors at crossing points.

The first and second conductors may be selected from the following: (a)the first electrical conductors are elongate bus bars and the secondelectrical conductors are flexible conductors of a flexible flat cablecomprising flexible insulation material in which the flexible conductorsthereof are held, (b) the first electrical conductors are individualflexible single-core wires, and the second electrical conductors areflexible conductors of a flexible flat cable comprising flexibleinsulation material in which the flexible conductors thereof are held,and (c) both the first and second electrical conductors are flexibleconductors of a flexible flat cable comprising flexible insulationmaterial in which the flexible conductors thereof are held. In addition,at a plurality of the crossing points, the mutually crossing first andsecond electrical conductors may be connected to each other to providethe desired electrical junctions.

In this aspect of the present invention, elongated bus bars and flexibleflat cables (FFC) are used. Alternatively, a FFC and a flexiblesingle-core wire (e.g. bare wires) or two FFCs may also be used in placeof the bus bars. The conductors on the one surface of the insulationsubstrate and the conductors on the other surface thereof are crossedand connected to each other, preferably by welding, at necessary crosspoints to form the desired circuit. Therefore, there is little loss ofthe conductive metal plate, whcih greatly improves the yield of theconductive metal plate. In addition, when it is the construction of thecircuit is changed, it is not necessary to alter the electricconductors, instead, only the positions at which the electric conductorsare connected to each other need to be changed. Accordingly, thejunction box of the present invention can be manufactured at a lowercost and provides easier alteration of the circuit.

In cases where a FFC and single-wire core (bare wire) are used incombination, or where only flexible flat cables are used in stead of abus bar it is unnecessary to remove the insulating coating material at aconnection position. The FFC contains the electric conductors arrangedin parallel with one another in the insulation film. Thus, it ispossible to dispose only one FFC containing a desired number of electricconductors laminated with the insulation film on the insulationsubstrate and thereby reduce the time and labor required for assembly.

The electric conductors may optimally be connected on the one surface ofthe insulation substrate and to those on the other surface thereof toeach other by resistance welding. However, soldering, ultrasonicwelding, laser welding or gas welding may also be used.

The connector module may include a plurality of circuit layerscomprising insulation substrates and conductors, stacked one uponanother with insulation plates interposed between the adjacent layers.The FFC has the electric conductors laminated with the insulation film.Thus when the bus bar, the single-core wire or the FFC is located at theinterface between two layers, they are insulated. In this case, the useof the insulation plate can be omitted.

In this specification the term “pressure connection” refers to theconnection of two conductors that is achieved by press-fitting agripping part onto a gripped part, the fitting force being maintained tokeep a permanent connection. In the embodiments, for example, a wire isinserted into a groove on the tab of a bus bar, which maintains agripping pressure on the wire.

The flexible conductors used in the invention should be selected to besuitably flexible without damage, e.g. to allow the connections throughthe insulating substrates. Their flexibility is in contrast to therelative rigidity of the bus bars, which generally retain their shape,though being capable of being deformed into a desired shape.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described by way ofnon-limitative example, with reference to the drawings, in which:

FIG. 1 is a schematic exploded perspective view of a junction box of afirst embodiment of the present invention;

FIG. 2 is a sectional view of the junction box of FIG. 1 in itsassembled state;

FIG. 3 is a sectional view on line III—III of FIG. 2;

FIG. 4 is a sectional view on line IV—IV of FIG. 2;

FIGS. 5A and 5B are front views of two side cases of the box of FIG. 1respectively;

FIG. 6A is a schematic perspective view of a layer of the connectormodule of the box of FIG. 1;

FIG. 6B is an enlarged sectional view showing a portion of the connectormodule of the box of FIG. 1;

FIG. 7A is a schematic sectional view of the connector module of the boxof FIG. 1;

FIG. 7B shows in plan a bus bar at the lowermost layer of the connectormodule; FIGS. 8A and 8B are explanatory diagrams showing a method offorming the connector module of the box of FIG. 1;

FIG. 9 is a side view of the junction box of FIG. 1 showing the fusemodule;

FIG. 10A is a partly sectional view of the fuse module of FIG. 9;

FIG. 10B is a schematic perspective view of the connections of the fusemodule of FIG. 9;

FIG. 11 is a plan view of a portion of the box of FIG. 1 showing therelay module;

FIG. 12A is a sectional view of the relay module of FIG. 11;

FIG. 12B is a schematic view showing the connections of the relay moduleof FIG. 11;

FIG. 12C is a schematic perspective view of a connection between a busbar and a wire in the relay module of FIG. 11;

FIG. 12D is a schematic perspective view of a connection between busbars in the relay module of FIG. 11;

FIG. 13 is a schematic perspective view of a portion of a modifiedconnector module for the box of FIG. 1;

FIG. 14A is an underneath view of an electrical junction box which is asecond embodiment of this invention;

FIG. 14B is a sectional view of the box of FIG. 14A;

FIG. 15 is a diagram showing the construction of the connector module ofthe box of FIGS. 14A and 14B;

FIG. 16A is a schematic perspective view of a layer of a modifiedconnector module for the box of FIG. 1;

FIG. 16B is a schematic sectional view of the layer of FIG. 16A;

FIG. 17 is a sectional view illustrating the assembly of the layers ofFIG. 16A of the modified connector module;

FIGS. 18A and 18B are schematic views of connections in the fuse module,when the modified connector module of FIGS. 16A and 17 is employed;

FIG. 19 is a schematic view of a connection in the relay module, whenthe modified connector module of FIGS. 16 and 17 is employed;

FIGS. 20A and 20B are diagrams illustrating manufacture of other formsof modified connector modules for the box of FIG. 1;

FIG. 21 is an exploded perspective view of a prior art junction box; and

FIGS. 22A and 22B are diagrams company a conventional junction box (FIG.22A) and a box of the present invention (FIG. 22B).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the different embodiments, the same reference numbers are used foridentical or similar parts.

FIG. 1 is a schematic exploded perspective view showing component partsconstituting an electrical junction box 10 intended to be connected to awire harness, not shown, in a vehicle, such as an automobile. FIGS. 2 to4 are sectional views showing the assembled state of the componentparts.

The junction box 10 has a connector module 11, a fuse module 12 and arelay module 13, housed in a casing having a lower case 14, an uppercase 15, an intermediate case 16 and opposite side cases 17, 18. Withinthe casing there may also be an electronic control unit 19. The cases14, 15, 16, 17 and 18 are moulded plastics bodies.

After the connector module 11, the intermediate case 16 and theelectronic control unit 19 may be sequentially disposed on the lowercase 14, the upper case 15 may be mounted on the electronic control unit19, and the side cases 17, 18 may be mounted on the connector module 11.The relay module 13 may be disposed over one side of the connectormodule 11 in such a way as to expose relays 40 of the relay module 13 tothe outside through an opening 15 a formed adjacent one side of theupper case 15. The fuse module 12 may be mounted on the connector module11 at one side thereof and exposed to the outside through an openingformed between the lower case 14 and the upper case 15.

A plurality of connector accommodation portions 70, 80 in the form ofreceiving sockets may be formed in a row on each of the side cases 17,18, which may be mounted at opposite sides of the lower case 14 and theupper case 15 in their widthwise direction. As shown in FIGS. 5A and 5B,the number of stages of terminals in each of the connector accommodationportions 70, 80 is three, namely, I, II and III, except at one socket ofeach where the number of stages of terminals is reduced.

As shown in FIGS. 6A and 6B, in each layer of the connector module 11,flexible single-core wires 21 in the form of bare wires of copper may bedisposed entirely on one surface (lower surface in FIGS. 5A and 5B) of athin planar insulation substrate 20 made of insulation resin in such away that the single-core wires 21 extend parallel with one another at aregular pitch in an X-direction. Long and narrow bus bars 22 in the formof metal strips of uniform width may be disposed on the other surface(upper surface) of the insulation substrate 20 in such a way that thebus bars 22 are parallel with one another at a regular pitch in aY-direction orthogonal to the X-direction. That is, the single-corewires 21 and the bus bars 22 cross each other, with the insulationsubstrate 20 interposed therebetween.

An opening 20 a through the substrate 20 may be formed at each ofselected positions 20 b where the single-core wires 21 and the bus bars22 cross each other. Through the opening 20 a, the single-core wire 21is flexed to join it to the bus bar 22. In this state, the single-corewires 21 and the bus bars 22 may be selectively welded to each other byresistance welding to form a desired circuit.

The two ends of each bus bar 22 in its longitudinal direction projectfrom the edges of the insulation substrate 20 in its widthwisedirection. The projecting portions may be bent twice in a zig-zag shapeas shown to form horizontal tabs 22 b, 22 c. The tabs 22 b and 22 c maybe arranged parallel with one another respectively on the same level.

The interval between the horizontally arranged tabs 22 b may be equal tothe interval between the adjacent terminal holes 70 a of the connectoraccommodation portion 70 of the side case 17. Similarly, the intervalbetween the horizontally arranged tabs 22 c is equal to that betweenadjacent terminal holes 80 a of the connector accommodation portion 80of the side case 18.

In this manner, a circuit plate 100 may be constructed of thesingle-core wires 21 and the bus bars 22 disposed as described above andconnected to each other at the required positions, with the insulationsubstrate 20 sandwiched between them. As shown in FIG. 7A, three suchcircuit plates 100, identified as 100A, 100B and 100C may be layeredvertically on each other with interposition of additional insulationplates 25 made of insulation resin. The tabs 22 b and 22 c of the busbar 22 of the three circuit plates 100 stacked vertically may bevertically spaced in correspondence to the interval between adjacentrows of the terminal holes 70 a, 80 a of the connector accommodationportions 70, 80 of the side case 17, 18. That is, the tabs of the busbars of the circuit plates 100A, 100B and 100C are level with theterminal holes of the first row, the second row and the third rowrespectively.

In the connector module 11, a bus bar 27, having a circuit configurationformed by punching a conductive metal plate in a conventional manner asshown in FIG. 7B may be disposed on a lower surface of the insulationplate 25 below the first circuit plate 100A. As shown in FIG. 1 also, atone end of the bus bar 27, there may be formed a plurality of fuseconnection pressure connection terminals 27 a arranged parallel with oneanother and projecting in the extension direction of the single-corewires 21. The terminals 27 a project from an edge of the module 11 asblades 27 b which are brought into contact with terminals of fuses inthe fuse module 12.

The three circuit plates 100A, 100B, 100C to be stacked in three layersmay be formed by a method shown in FIG. 8.

Initially, a rib or spigot (not shown) projecting from one surface ofeach of the respective insulation substrates 20 may be inserted into anopening formed in each of its bus bars 22 and deformed to fix the busbars to the insulation substrate 20 parallel to each other.

In this case, the width W (see FIG. 8B) of the insulation substrates 20may be set to the following relationship: 100A>100B>100C. The length ofthe bus bar 22 may be larger than the width of the insulation substrate20. The bus bars 22 project from both sides of the insulation substrate20 in its widthwise direction. The projecting portion of each bus bar 22may be bent vertically and then bent horizontally to form the horizontaltabs 22 b, 22 c.

The three insulation substrates 20 are arranged in a row spaced atrequired intervals, with the middle substrate 20 inverted with respectto the outer two substrates 20, as shown in FIG. 8A.

Thereafter, the single-core wires 21 are continuously extended parallelwith one another across the three insulation substrates 20. Because thesurfaces to which the bus bars are fixed are alternately inverted, asdescribed above, each single-core wire 21 may be continuously disposedacross the upper surface of the substrate 20 in the circuit plate 100A,the lower surface thereof in the circuit plate 100B, and the uppersurface thereof in the circuit plate 100C. Gaps may be provided betweenthe adjacent substrates 20 in the row, and the wires 21 extend inparallel with one another in the gaps (see FIG. 8B).

Thereafter, the bus bars 22 and the single-core wires 21 may be joinedwith each other by resistance welding through the openings 20 a. Thewires 21 at the gaps between the substrates may be then flexed, to bringthe substrates 21 into their stacked positions, as shown by arrows inFIG. 8A. Unwanted portions of the continuous wires 21 may be cut offbefore and/or after the circuit plates 100A-100C are stacked one uponanother. Portions of the bus bars may also be removed.

This manufacturing method is simple, with a small number of operations.

As described above, the fuse connection terminals 27 a project parallelwith one another from the lowermost end of one edge (left edge inFIG. 1) of the connector module 11. In mounting the connector module 11on the lower case 14, the terminals 27 a may be disposed on a portion 14b formed at one edge (left edge in FIG. 1) of the lower case 14 havingpartitions to hold the terminals 27 a in position. The single-core wires21 of each circuit plate 100 may be disposed above the pressureconnection terminals 27 a.

The fuse module 12 may be disposed at the left edge of the connectormodule 11. As shown in FIG. 9, the fuse module 12 has a plurality offuse accommodation portions 31 in the form of sockets arranged widthwisein parallel with one another in a moulded plastics body 30. The sockets31 may be in upper and lower stages.

As shown in FIGS. 10A and 10B, bus bars 33 are insert moulded in thematerial of the body 30. At opposite ends of each bus bar 33, there isformed a pair of pressure connection terminals 33 a, 33 b. A pair ofsuch terminals projects into each fuse accommodation portion 31 a at theupper stage of the fuse module 12 as power supply side and load sideterminals. A load side terminal formed on another bus bar 33 projectsinto each fuse accommodation portion 31 b at the lower stage of the fusemodule 12. One end of each L-shaped bus bar 33 projects into therespective fuse accommodation portion 31 a, 31 b, whereas the other endthereof extends toward the upper surface of one of the single-core wires21. The pressure connection terminal 33 b may be connected to therequired single-core wire 21 by pressing the wire into the slot of theterminal. The pressure connection terminal 33 a projected into the fuseaccommodation portions 31 a, 31 b may be connected to the terminal ofthe fuse also by pressure. In the lower stage fuse accommodation portion31 b, the terminals at the power supply side are the pressure connectionterminals 27 a of the bus bar 27 described above.

A fuse 35 may be inserted into the fuse accommodation portions 31 a, 31b of the fuse module 12 to connect a pair of terminals 35 a, 35 b of thefuse 35 to a pressure connection terminal 33 a of the bus bar 33 or thepressure connection terminal 27 a formed on the bus bar 27 at thelowermost layer of the connector module 11 by press fitting.

As shown in FIG. 12D, some of the bus bars 41 may be directly connectedto tabs 33 c of the bus bars 33 of the fuse module 12 by pressureconnection.

In the relay module 13, as shown in FIGS. 11 and 12, bus bars 41 may beinsert moulded in the plastics material of the moulded body 42. Relays40 may be received on the outer face of the body 42. Terminals 40 a ofthe relay 40 may be inserted into openings 42 a and 41 a in the body 42and the bus bar 41 respectively and directly mounted on the body 42 withsolder 43.

As shown in FIGS. 12B and 12C one portion of the bus bar 41 welded tothe terminal 40 a of the relay 40 may be bent to form a pressureconnection terminal 41 b at the front end of the bus bar 41. Theterminal 41 b may be connected to one of the single-core wires 21 bypressure fitting.

The electronic control unit 19 has electronic parts 51 mounted on alower surface of a substrate 50. The substrate 50 may be placed onsupports 53 projecting upwardly at four corners of the intermediate case16. Screws 54 may be screwed into screw holes 53 a and 50 a formed in anupper surface of the support 53 and the substrate 50 respectively to fixthe substrate 50 to the intermediate case 16. In this state, theelectronic parts 51 may be located in a space between the substrate 50and the intermediate case 16.

A plurality of printed electric conductors arranged in parallel with oneanother at one edge of the substrate 50 may be connected to the upperend of a vertically extending assembly of relay terminals 56 through anECU connector 58 (FIG. 3) or directly. Pressure connection terminals maybe formed at the lower end of the relay terminals 56 to connect withsingle-core wires 21 of the connector module 11 by pressure fitting.

In the junction box 10 composed of the above-described component parts,the connector module 11, the intermediate case 16 and the electroniccontrol unit 19 may be stacked one upon another sequentially on thelower case 14. The electric conductors of the electronic control unit 19may be connected to the single-core wires 21 of the connector module 11through the relay terminals 56 by pressure connection. The fuse module12 may be mounted on the connector module 11 at one side thereof toconnect the pressure connection terminals 33 b disposed at one end ofthe bus bars 33 of the fuse module 12 to the single-core wires 21 of theconnector module 11. The relay module 13 may be mounted on an upper partof the connector module 11 to connect the pressure connection terminalsof the bus bars 41 of the relay module 13 to the single-core wires 21 ofthe connector module 11.

In the junction box 10 having the above-described construction, the tabs22 b, 22 c formed at the ends of each of the bus bars 22 of theconnector module 11 project into the terminal holes of the connectoraccommodation portions 70, 80 of the side cases 17, 18 and in use makeconnection to connectors (not shown) of a wire harness (not shown).

Because the connector may be connected to the wire harness on the sidesurface of the junction box, it is unnecessary to connect the wireharness to the horizontal surface of the lower case 14 or the upper case15. Thus it is unnecessary to provide space for the wire harness belowthe lower case or above the upper case. Accordingly, it is possible toreduce the space required in the vehicle for the wire-harnessconnection.

As shown schematically in FIG. 22B, the electrical conductors of theconnector module 11 are the bus bars and the single-core wires crossingthe bus bars. The single-core wires and the bus bars may be connected toeach other by resistance welding at the required crossing positions toform a circuit. Thus the connector module 11 can be connected to aconnector and a fuse without increasing the number of layers of the busbars.

To form the bus bars 22, it is not necessary to punch a conductive metalplate in correspondence to the specific configuration of a circuit.Standard uniform width strip metal may be used. Therefore, it ispossible to greatly improve the yield of the conductive metal plate. Inaddition, it is easy to alter the construction of the circuit bychanging the positions where the bus bars 22 and the single-core wires21 may be welded to each other.

The use of the flexible wires 21 allows thermal stress at the weldinglocations to be absorbed.

The electrical conductors of the connector module may be connected tothose of the fuse module and the relay module by connecting the pressureconnection terminals at the ends of the bus bars of the fuse module andthe relay module to the single-core wires 21 of the connector module 11collectively (in a single operation) by pressure fitting, instead of bywelding of bus bars. Therefore, it is possible to reduce the number ofwelding operations and hence improve ease of manufacture.

In the modified connector module shown in FIG. 13, in the uppermostcircuit plate 100A, near one edge of the insulation substrate 20, a pairof holes 20 b and 20 c for insertion of pressure connection blades maybe formed at positions on both sides of each single-core wires 21. Thepressure connection terminals of bus bars of the relay module 13,described above, may be connected to an intermediate portion of thesingle-core wires 21 of the circuit plate 100A, by inserting the bladesof the terminals inserted into the holes 20 b and 20 c.

As shown in FIG. 13, the electric conductors (bus bars) of the relaymodule can be connected to the intermediate portions of the single-corewires 21 by pressure connection. Thereby it is possible to connect thecircuit of the connector module to that of the relay module by pressureconnection, instead of welding of bus bars.

Because the relay module may be connected to the intermediate portionsof the single-core wires 21, it is possible to utilize both ends of thesingle-core wires for pressure connection between the wires and othermodules, namely, the bus bars of the fuse module and also for pressureconnection between the wires and the electronic control unit.

In addition, simplification can be achieved by connecting the circuit ofthe relay module, the fuse module and the electronic control unit to thesame single-core wire of the conductor module.

Because the connector module has the largest number of circuits andrequires many variations of its circuit construction, wires and bus barsmay be used as the electric conductors thereof. They may be crossed andwelded to each other at selected crossing positions to form the desiredcircuit thereof. Therefore, it is possible to achieve easy alteration ofthe circuit construction by merely changing the positions where the busbars and the single-core wires may be connected to each other.

The present invention is not limited to the above-described embodiments.For example, the tab formed at both ends of the bus bars may projectinto the terminal hole of the connector accommodation portion, with thetab being flat and not bent.

FIGS. 14A and 14B shows a further modification of the junction box ofFIG. 1. Instead of using the side cases having the connectoraccommodation portions, the casing may be constructed of an upper case15′ and a lower case 14′ in which connector accommodation portions 14 a′may be formed. In this case, as shown in FIG. 15, the tabs 22 a of thebus bars 22 of the connector module 11′ may be bent downward withrespect to the insulation substrate 20.

In the above embodiments, single-core wires may be used in the connectormodule. Instead, it is possible to use a single-core wire coated with aninsulation coating material. In this case, the insulation coatingmaterial may be removed at the locations where the wire and the bus barare welded to each other.

It is possible in the fuse module and the relay module to use circuitslike the connector circuit described above having bus bars disposed onone surface of the insulation substrate and the electrical wiresdisposed on the other surface thereof, to connect to the fuse terminalsand relay terminals.

As apparent from the foregoing description, in the illustrated junctionbox of the present invention, as the electric conductors of theconnector module, the long and narrow bus bars and the single-core wiresare arranged crossing each other, with the insulation substrateinterposed between them and welded to each other at crossing points toform the circuit of the connector module. Therefore, it is possible toinsert the tabs at both ends of the bus bars into the terminal holes ofthe connector accommodation portions formed on the side cases. Furtherthe gap between the bus bars is equal to the gap between the terminalholes. In addition, the gaps between the tabs of the bus bars in therespective layers of the stack of circuit plates is equal to the spacingbetween the rows of the terminal holes of the connector accommodationportions. Thereby by making the number of the circuit plates layered oneupon another is equal to the number of the rows of the terminals of theconnector accommodation portions and by using the long and narrow stripbus bars, it is easy to form the connector accommodation portionswithout bending the bus bars in a complicated manner.

Further since the connectors may be received at the side surface of thecase of the junction box, the bus bars do not need to be arranged in acomplicated manner. The long and narrow strip bus bars are arrangedparallel with one another in a simple manner.

Furthermore, by the use of the long and narrow bus bars, it is possibleto reduce the manufacturing cost considerably, as compared with the casein which the bus bars are formed as complicated shapes in correspondenceto the configuration of a circuit. Thus when a re-design of the circuitis needed the construction of the present invention can achievealteration of the circuit construction by merely changing the positionof connection between the wires and the bus bars.

Further variations of the connector module 11 will now be described.

In the modified connector module of FIGS. 16A, 16B and 17, flexiblewires in the form of sectionally rectangular electrical conductors 21consisting of copper may be disposed on one surface (lower surface inFIGS. 16A) of the thin insulation substrate 20 made of insulation resinin such a way that the electric conductors 21 are parallel with oneanother at a regular pitch in the X-direction. Upper and lower surfacesof the conductors 21 may be laminated with insulation films 28, 29 toform a wide flexible flat cable (FFC). Elongate bus bars 22 may bedisposed on the other surface (upper surface) of the insulationsubstrate 20 in the same manner as shown in FIGS. 6A and 6B etc. above.The electric conductors 21 of the FFC 24 and the bus bars 22 cross eachother, with the insulation substrate 20 interposed therebetween.

As shown in FIG. 16B, an opening 20 a is formed at each of selectedpositions where the conductors 21 and the bus bars 22 cross each other.At each hole, the insulation films 28, 29 of the FFC 24 are separatedfrom the conductor 21 to expose the conductor 21, which may be flexedthrough the opening 20 a of the insulation substrate 20. In this state,a flexed portion 21 x of the conductor 21 and the bus bar 22 may bewelded to each other by resistance welding to form a required circuitconnection of the FFC 24 and the bus bars 22.

In this manner, a circuit plate 100 (100A-100C) is constructed of theFFC 24 and the bus bars 22 disposed as described above and connected toeach other at the required positions, with the insulation substrate 20sandwiched therebetween. As shown in FIG. 17, three circuit plates 100are layered vertically on each other through insulation plates 26 madeof insulation resin.

In this connector module, as shown in FIG. 17, a bus bar 27, having acircuit configuration formed by punching a conductive metal plate may bedisposed on a lower surface of the lower circuit plate 100A through aninsulation plate 25, as in the above embodiment.

The three circuit plates 100 (100A-lOOC) disposed in three layers may beformed by the method shown in FIGS. 8A and 8B, substituting the array ofwires 21 of FIGS. 8A and 8B by the single FFC 24 which may be laidacross the three substrates.

Portions of the conductors 21 which are not wanted in the circuit of thecontinuous FFC 24 may be cut off before and/or after the circuit plates100A-100C are layered one upon another.

In the layered state, the FFC 24 may be disposed on the lower surface ofthe insulation substrate 20, and the bus bars 22 may be disposed on theupper surface thereof, with the insulation substrate 20 interposedbetween the FFC 24 and the bus bars 22. Between the adjacent circuitplates 100A-100C, the FFC 24 and the bus bars 22 confront each other,with the insulation plates 26 interposed therebetween.

FIGS. 18A and 18B show how, in a manner similar to that of FIG. 10B, thepressure connection is made between the bus bars 22 of the fuse moduleand the conductors 21 of the FFC 24. It is not necessary to remove theinsulation 22, 23 before pressing the bus bar 33 and the FFC 24together. FIG. 19 likewise shows the pressure connection made betweenthe bus bars 41 of the relay module and the conductors 21 of the FFC 24.

The connections of the FFC 24 to the electronic control unit via therelay terminals 56 may also be carried out by pressure connections.

FFC 24 may be used in other versions of the connector module 11. Forexample, as shown in FIG. 20A, in the connector module, flexiblesingle-core wires 60 similar to the wires 21 of FIGS. 6A and 6B may bedisposed on one surface of the insulation substrate 20 and the FFC 24may be disposed on the other surface thereof. Alternatively, FFCs may bedisposed on both surfaces of the insulation substrate 20 as shown inFIG. 20B. In both cases, the electrical conductors on the two surfacesof the insulation substrate 20 are orthogonal to each other and crosseach other. The electrical conductors may be connected at selectedcrossing points by bending and/or welding.

It is also possible to have the FFC project into the connectoraccommodation portion, instead of the tabs of the bus bars, to connectthe conductors of the FFC to a connector at a wire harness side.

Furthermore the FFC may be used as a wire harness by extending the FFCfrom the connector module, namely to connect it to other component partsof the vehicle body. That is, the FFC may be extended outside thejunction box to serve as an external harness.

From this embodiment it is apparent that, in the junction box of thepresent invention, because the connector module has the largest numberof circuits and requires alteration of its circuit configuration,electric wires, elongate bus bars, and the FFC (or FFC and electricwires or only FFC) may be used as the electric conductors thereof. Theelectric conductors cross and may be welded to each other at crossingpositions to form the circuit. When the FFC is used the bus bars do notnecessarily have to be used.

The FFC can be very easily disposed continuously on one surface of theinsulation substrates with the insulation substrates arranged in a row,thus simplifying the manufacture.

While the invention has been described in conjunction with the exemplaryembodiments described above, many equivalent modifications andvariations will be apparent to those skilled in the art when given thisdisclosure. Accordingly, the exemplary embodiments of the invention setforth above are considered to be illustrative and not limiting. Variouschanges to the described embodiments may be made without departing fromthe spirit and scope of the invention.

What is claimed is:
 1. An electrical junction box comprising: a casing,and an electrical circuit in said casing adapted to make electricalconnection, in use, to electrical connectors, fuses and relays, saidelectrical circuit comprising a fuse connection circuit, a relayconnection circuit and a connector connection circuit, which iselectrically connected to said fuse connection circuit and said relayconnection circuit, said casing comprising a fuse circuit portion,containing said fuse connection circuit, and a relay circuit portion,containing said relay connection circuit, said casing having twolaterally opposite sides at each of which said casing comprises aconnector accommodation portion adapted to receive, in use, at least oneelectrical connector, said electrical junction box further comprising,mounted in said casing, a connector module providing said connectorconnection circuit and comprising (i) a plurality of insulationsubstrates stacked one on another and each having a first main surfaceand a second main surface opposite said first main surface, (ii) aplurality of parallel elongate bus bars arranged on said first mainsurface of each said substrate and extending in a first direction, and(iii) a plurality of parallel flexible conductors arranged on saidsecond main surface of each said insulation substrate and extending in asecond direction orthogonal to said first direction, wherein each saidinsulation substrate has a plurality of apertures through it from saidfirst main surface to said second main surface, at which said bus barsand said flexible conductors are connected to each other by welding toprovide desired circuit connections, and said first direction of saidbus bars of each said insulation substrate is the lateral direction ofsaid casing between said opposite sides, at least some of said bus barsextending from said insulation substrates in said first direction andproviding tabs projecting into said connector accommodation portions. 2.An electrical junction box according to claim 1, wherein said flexibleconductors of said connector module are single-core wires.
 3. Anelectrical junction box according to claim 1, wherein said flexibleconductors of each said insulation substrate are conductors of aflexible flat cable arranged on said second main surface of theinsulation substrate, said flexible flat cable comprising flexibleinsulation material in which said conductors are held.
 4. An electricaljunction box according to claim 1, wherein said connector accommodationportions have a plurality of stages, one above another, at which aplurality of rows of terminals of at least one connector are received,in use, the number of said insulation substrates of said connectionmodule being equal to the number of said stages.
 5. An electricaljunction box according to claim 1, wherein said connector module has, inaddition to said bus bars of said insulation substrate, at least oneadditional layer of bus bars mounted on the stack of said insulationsubstrates in a parallel direction relative to the insulationsubstrates, wherein said connector accommodation portions have aplurality of stages, one above another, at which a plurality of rows ofterminals of at least one connector are received, and wherein the totalnumber of said insulation substrates and the number of said layers ofsaid at least one additional layer of bus bars being not less than thenumber of said stages.
 6. An electrical junction box according to claim1, wherein said bus bars providing said tabs are bent at end portionsthereof projecting from said insulation substrates so that said tabs aredisplaced, in the stacking direction of the insulation substrates,relative to said first main faces of said insulation substrates.
 7. Anelectrical junction box according to claim 1, mounted on a vehicle. 8.An electrical junction box comprising: an electrical circuit adapted tomake electrical connection, in use, to electrical connectors, fuses andrelays, said electrical circuit comprising a fuse connection circuit, arelay connection circuit and a connector connection circuit which iselectrically connected to said fuse connection circuit and said relayconnection circuit, wherein at least one of said fuse connectioncircuit, said relay connection circuit and said connector connectioncircuit comprises a circuit module having a plurality of elongate busbars arranged parallel to each other and extending in a first directionand a plurality of flexible conductors arranged parallel to each otherand crossing said bus bars in a second direction orthogonal to saidfirst direction, said flexible conductors and said bus bars beingelectrically connected to each other at a plurality of their mutualcrossing points to provide desired circuit connections.
 9. An electricaljunction box according to claim 8 wherein said circuit module has aninsulation substrate having first and second opposite main surfaces onwhich said bus bars and said flexible conductors are respectivelyarranged, and having apertures through it from said first main surfaceto said second main surface to enable said desired circuit connectionsto be formed through said apertures.
 10. An electrical junction boxaccording to claim 9, wherein said flexible conductors are bare coppersingle-core wires.
 11. An electrical junction box according to claim 9,wherein said bus bars and said flexible conductors are joined at saiddesired circuit connections by one of resistance welding and soldering.12. An electrical junction box according to claim 9, wherein saidcircuit module has a plurality of insulation substrates stacked one uponanother, each having first and second opposite main surfaces, thesebeing a plurality of sets of said mutually orthogonally crossingflexible conductors and bus bars arranged respectively on the first andsecond surfaces of the respective insulation substrates.
 13. Anelectrical junction box according to claim 9, mounted in a vehicle.